Electrically switchable behavior in coupled EIT-like meta-molecule and Fabry-Pérot cavity

In this paper, we propose a microstrip Fabry-P & eacute;rot (FP) cavity embedded with an active electromagnetically-induced-transparency-like (EIT-like) meta-molecule to investigate the electrically switchable behavior. The phenomenon of EIT is achieved by coupling a 'bright' comb-line resonator with a 'dark' split-ring resonator. The FP cavity is fabricated by etching two narrow slots on a microstrip line. With two different resonance mechanisms working together, the proposed composite EIT-cavity design is shown to exhibit the enhanced EIT-like transmission characteristics, accompanied by two sharp Fano-type line-shapes. By incorporating PIN diodes into the composite EIT-cavity structure, we can dramatically modulate the transmission spectrum via external DC voltage. In particular, we show the multi-band unity modulations through biasing the proposed active samples. Moreover, the slow light on-to-off switching processes are also obtained with modifying the state of PIN diode from dielectric to conductive. Our results may open important opportunities for fabricating dynamic functional photonic devices in the future.